Prepare inhibitors of chymotrypsin/elastase, pepsin, carboxypeptidases A and B, and trypsin from the same crude extract of Ascris by using affinity chromatography. The preparations of inhibitors will be used to: a. Complete the primary sequence of chymotrypsin/elastase inhibitors. b. Assign the disulfide bridge pairings in the chymotrypsin/elastase inhibitors. c. Locate the lysine residue(s) in Ascaris trypsin inhibitor which responds to maleoylation as if it were located in the P1 site. (Arginine is in the P1 site.) d. Study binding of Ascaris pepsin inhibitor to derivatives of pepsin formed when pepsin is reacted with active site directed reagents. Establish the conditions for crystallization of the pepsin-Ascaris pepsin inhibitor complex. e. Determine the primary structure of the Ascaris carboxypeptidase inhibitor. Determine whether the concentration of proteinase inhibitors in Ascaris eggs and larvae is correlated with stages in their biological development. Complete the life cycle of "lung stage hog Ascaris larvae" in vitro by showing the need for hog stomach juice and then pancreatic juice in the nutrient media. Determine what happens to host proteolytic enzymes when they encounter live adult Ascaris. Establish whether Ascaris intestines have digestive enzymes that are capable of hydrolyzing host proteins. Determine how live Ascaris respond to lipase, amylase, ribonuclease and deoxyribonuclease, other host pancreatic enzymes, which are also present in their environment.